DDR4 memory chips inoramba iri panjodzi yekurwiswa neRowHammer kunyangwe yakawedzerwa dziviriro

Chikwata chevaongorori kubva kuVrije Universiteit Amsterdam, ETH Zurich neQualcomm kupedza kudzidza kwekushanda kwedziviriro kubva kukurwisa kwekirasi kunoshandiswa mune yazvino DDR4 memory chips RowHammer, ichikubvumidza kuti uchinje zvirimo zvega zvega zvimedu zvesimba risingaverengeki rekuwana memory (DRAM). Mhedzisiro yacho yaiodza moyo uye DDR4 machipi kubva kuvagadziri vakuru vachiri sarai panjodzi (CVE-2020-10255).

Kusagadzikana kweRowHammer kunobvumira zviri mukati mememory bits kuti zvikanganiswe nekutenderera kuverenga data kubva padyo nememory maseru. Sezvo DRAM ndangariro iri maviri-dimensional array emaseru, rimwe nerimwe rine capacitor uye transistor, kuita kuenderera kuverenga kwenzvimbo imwechete yekurangarira kunoguma nekushanduka kwevoltage uye anomalies izvo zvinokonzeresa kurasikirwa kudiki kwechaji mumaseru akavakidzana. Kana kuverenga kwakanyanya kwakakwira zvakakwana, saka sero rinogona kurasikirwa nemutengo wakakura wakaringana uye kutenderera kunotevera kwekuzvarwa patsva hakuzove nenguva yekudzorera mamiriro ayo ekutanga, izvo zvinozoita shanduko mukukosha kweiyo data yakachengetwa muchitokisi. .

Kuvharisa mhedzisiro iyi, yemazuva ano maDDR4 machipi anoshandisa TRR (Target Row Refresh) tekinoroji, yakagadzirirwa kudzivirira maseru kubva pakushatiswa panguva yekurwiswa kweRowHammer. Dambudziko nderekuti hapana nzira imwe chete yekushandisa TRR uye imwe neimwe CPU uye mugadziri wekuyeuka anodudzira TRR nenzira yayo, inoshandisa ayo ekudzivirira sarudzo uye haiburitse ruzivo rwekuita.
Kudzidza nzira dzekuvharisa dzeRowHammer dzinoshandiswa nevagadziri zvakaita kuti zvive nyore kutsvaga nzira dzekunzvenga dziviriro. Pakuongororwa, zvakaonekwa kuti musimboti unoitwa nevagadziri ".kuchengetedzwa kuburikidza nekusajeka (kuchengetedzeka nekusajeka) pakushandisa TRR inobatsira chete kudzivirira mune dzakakosha zviitiko, kuvhara kurwiswa kwakajairwa kunodzora shanduko mukuchaja kwemasero mumutsara mumwe kana miviri yakatarisana.

Chishandiso chakagadzirwa nevatsvaguri chinoita kuti zvikwanise kutarisa kusanzwisisika kwemachipi kune akasiyana siyana eiyo RowHammer kurwisa, umo kuyedza kupesvedzera kubhadharisa kunoitirwa mitsara yakati wandei yemaseru endangariro kamwechete. Kurwiswa kwakadaro kunogona kupfuura kudzivirira kweTRR kunoitwa nevamwe vagadziri uye kutungamirira kuhuwori hwendangariro, kunyangwe pahardware nyowani ine DDR4 memory.
Pamakumi mana nemaviri DIMMs akadzidzwa, gumi nematatu mamodule akave ari panjodzi kune asiri-standard akasiyana eRowHammer kurwisa, kunyangwe yakaziviswa kuchengetedzwa. Iwo anonetsa modules akagadzirwa naSK Hynix, Micron uye Samsung, vane zvigadzirwa zvifukidzo 95% yemusika weDRAM.

Pamusoro peDDR4, LPDDR4 machipi anoshandiswa munharembozha akadzidzwawo, izvo zvakazoratidza kuve nehanya nemhando yepamusoro yekurwiswa kweRowHammer. Kunyanya, ndangariro yakashandiswa muGoogle Pixel, Google Pixel 3, LG G7, OnePlus 7 uye Samsung Galaxy S10 smartphones yakakanganiswa nedambudziko.

Vatsvagiri vakakwanisa kuburitsa akati wandei nzira dzekushandisa pane zvinetswa DDR4 chips. Semuenzaniso, kushandisa RowHammer-exploit yePTE (Peji Tafura Entries) zvakatora kubva pamasekondi 2.3 kusvika kumaawa matatu nemasekonzi gumi nemashanu kuwana ropafadzo yekernel, zvichienderana nemachipisi akaedzwa. Kurwisa yekukuvara kukiyi yeruzhinji yakachengetwa mundangariro, RSA-2048 yakatora kubva pa74.6 masekonzi kusvika 39 maminetsi 28 seconds. Kurwisa zvakatora maminetsi makumi mashanu nemana nemasekonzi gumi nematanhatu kupfuura cheki cheki kuburikidza nekugadziriswa kwendangariro kweiyo sudo process.

Chishandiso chakaburitswa kutarisa maDDR4 memory chips anoshandiswa nevashandisi TRRespass. Kuti ubudirire kuita kurwiswa, ruzivo nezve marongerwo emakero emuviri anoshandiswa mukudzora ndangariro zvine chekuita nemabhangi nemitsara yemaseru ekurangarira inodiwa. Chishandiso chakagadziridzwa zvakare kuti chitarise marongerwo dhurama, izvo zvinoda kumhanya semudzi. Munguva pfupi iri kutevera zvakare zvakarongwa buritsa application yekuyedza smartphone memory.

Makambani Intel и AMD Kuti dzidzivirire, ivo vakaraira kushandisa kukanganisa-kugadzirisa ndangariro (ECC), ndangariro dzinodzora neMaximum Activate Count (MAC) tsigiro, uye shandisa yakawedzera mwero wekuzorodza. Vatsvagiri vanotenda kuti kune yakatoburitswa machipi hapana mhinduro yekuchengetedzwa kwakavimbiswa kubva kuRowhammer, uye kushandiswa kweECC uye kuwedzera kuwanda kwekurangarira kudzoreredzwa kwakave kusashanda. Somuenzaniso, zvakambotaurwa nzira kurwisa paDRAM ndangariro ichipfuura ECC dziviriro, uye zvakare inoratidza mukana wekurwisa DRAM kuburikidza Local area networkkubva guest system и nerubatsiro kushandisa JavaScript mubrowser.

Source: opennet.ru